package itemoccurrences

import (
	"fmt"
	"sort"

	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd"
	itemregistry "gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/items/registry"
	"gitea.maximumdirect.net/eric/notarius/internal/modules/dnd/shared"
)

type orderedItemOccurrence struct {
	value       dnd.ItemOccurrence
	earliest    int
	hasEvidence bool
}

func canonicalItemOccurrenceList(response extractionResponse, order shared.SourceRefOrder, sourceID string, registry *itemregistry.Registry) (dnd.ItemOccurrenceList, error) {
	if response.Occurrences == nil {
		return dnd.ItemOccurrenceList{}, nil
	}
	ordered := make([]orderedItemOccurrence, len(response.Occurrences))
	for index, occurrence := range response.Occurrences {
		item, found := registry.Lookup(occurrence.Name)
		if !found {
			return dnd.ItemOccurrenceList{}, fmt.Errorf("occurrences[%d].name is not in the item registry", index)
		}
		refs := order.Canonicalize(itemOccurrenceSourceRefs(occurrence.SourceRefs, sourceID))
		earliest, hasEvidence := order.EarliestValid(refs)
		ordered[index] = orderedItemOccurrence{
			value: dnd.ItemOccurrence{
				ItemID:     item.ID,
				Name:       item.Name,
				Kind:       dnd.ItemOccurrenceKind(occurrence.Kind),
				Quantity:   cloneQuantity(occurrence.Quantity),
				From:       occurrence.From,
				To:         occurrence.To,
				SourceRefs: refs,
			},
			earliest:    earliest,
			hasEvidence: hasEvidence,
		}
	}
	sort.SliceStable(ordered, func(left, right int) bool {
		if ordered[left].hasEvidence != ordered[right].hasEvidence {
			return ordered[left].hasEvidence
		}
		if !ordered[left].hasEvidence {
			return false
		}
		return ordered[left].earliest < ordered[right].earliest
	})
	occurrences := make([]dnd.ItemOccurrence, len(ordered))
	for index, occurrence := range ordered {
		occurrences[index] = occurrence.value
	}
	return dnd.ItemOccurrenceList{Occurrences: occurrences}, nil
}

func itemOccurrenceSourceRefs(refs []itemOccurrenceSourceRefResponse, sourceID string) []source.SourceRef {
	if refs == nil {
		return nil
	}
	values := make([]source.SourceRef, len(refs))
	for index, ref := range refs {
		values[index] = source.SourceRef{SourceID: sourceID, StartUnitID: ref.StartSegment, EndUnitID: ref.EndSegment}
	}
	return values
}

func cloneQuantity(value *int) *int {
	if value == nil {
		return nil
	}
	quantity := *value
	return &quantity
}